Chapter 9: Weather Factors Section 3: Winds

What is Wind? Wind – horizontal movement; from high pressure to lower pressure. Caused from differences in pressure Difference in pressure – caused by unequal heating of the atmosphere.

Measuring Wind Winds are described by their direction and speed. Name of wind – Where it comes from

Measuring Wind Wind speed is measured with an anemometer.

Wind-Chill Factor Wind-Chill Factor – the increased cooling caused by wind.

Local Winds Local Winds – blow over short distances. Caused by unequal heating of Earth’s surface within a small area. Form only when large scale winds are weak.

Local Winds Sea Breeze (Lake Breeze) – a local wind that blows from an ocean or lake.

Local Winds Land Breeze – flow of air from land to a body of water.

Global Winds Global Winds – winds that blow steadily from specific directions over long distances. Created by unequal heating of Earth’s surface but occur over a large area.

Global Convection Currents Global Convection Currents – Temperature differences between the equator and the poles produce giant convection currents in the atmosphere.

Global Convection Currents Coriolis Effect – Earth’s rotation makes winds curve.

Global Wind Belts Doldrums – Near Equator; Calm area; warm air rises; low pressure area Horse Latitudes – Calm area; falling air; high pressure Trade Winds – blow from horse latitudes toward the equator Prevailing Winds – blow away from the horse latitudes toward the poles